Cambium

Cost discipline and bounded agency for LLM call sites — the deterministic spine decides what to ask, the model only answers.

What it is

Cambium is the cost-discipline / bounded-agent layer that sits in front of your model calls. Instead of handing an LLM every decision, it routes work through the cheapest path that can answer it and only pays for the model when nothing cheaper will do. Three deterministic, pure-Python capabilities anchor the public surface:

• cambium.distill — pre-call payload minimization. Decide whether a payload even needs the model (assemble / pass / condense / summarize), shrink oversized payloads deterministically, and record what every call cost via a CostLedger.
• cambium.resolve — a cost-tiered resolution ladder. Try resolvers in cost order (deterministic → statistical → generative) and stop at the first one confident enough; the expensive generative tier is a budget-gated last resort.
• cambium.adapt — the feedback substrate for outcome-driven learning: record predictions, observe real outcomes, score them, and attribute credit/blame across the features and strategies that produced them.

The package import name is cambium; the PyPI distribution is cambium-ai.

Install

pip install cambium-ai

The core (distill / resolve / adapt) has no LLM dependency. Live generative clients are optional extras:

pip install "cambium-ai[claude]"   # live Anthropic client
pip install "cambium-ai[gemini]"   # live Gemini generator

cambium.distill — pre-call payload minimization + cost ledger

prepare runs the full routing pipeline and hands back a ready-to-send payload plus the accounting the ledger needs. Route.ASSEMBLE means no model call at all.

from cambium.distill import prepare, Route, CostLedger

prepared = prepare(task_output, budget_tokens=2000)
ledger = CostLedger(job_id="research-run")

if prepared.route is Route.ASSEMBLE:
    answer = format_table(task_output)                 # deterministic, no model
    ledger.record_avoided(label="summary", route="assemble",
                          tokens_saved=prepared.tokens_saved)
else:
    response = claude.call(prompt_with(prepared.content))   # your model call
    ledger.record(label="summary", model="claude-3-5-haiku",
                  input_tokens=response.input_tokens,
                  output_tokens=response.output_tokens,
                  tier="generative", tokens_saved=prepared.tokens_saved)

report = ledger.report
report.within_budget(max_cost_usd=0.05)   # cost-regression gate

estimate_tokens(content) and condense(content, max_tokens=...) are also public if you want the pieces directly.

cambium.resolve — cost-tiered resolution ladder

Implement a Resolver per tier and let resolve climb only as far as it must. The generative tier is skipped once the ledger is over budget.

from cambium.resolve import Tier, Resolution, resolve
from cambium.distill import CostLedger

class ExactMatch:
    tier = Tier.DETERMINISTIC
    name = "exact_match"
    def resolve(self, request):
        hit = lookup(request)
        if hit is None:
            return None
        return Resolution(value=hit, confidence=1.0, tier=self.tier)

ledger = CostLedger()
result = resolve(
    request,
    [ExactMatch(), embedding_resolver, llm_resolver],
    ledger=ledger,
    threshold=0.8,
    max_cost_usd=0.05,   # gates the generative tier
)

resolve returns the first resolution at/above threshold, else the best below-threshold one, else None. ResolverRegistry is available for grouping resolvers by decision type.

cambium.adapt — outcome-driven feedback substrate

Record predictions, feed back real outcomes, and mature them into scored attributions that a reweighting layer can consume.

from cambium.adapt import (
    PredictionRecord, OutcomeRecord, InMemoryPredictionLedger, mature,
)

led = InMemoryPredictionLedger()
led.record_prediction(PredictionRecord(
    id="p1", subject="AAPL", strategy="momentum",
    features={"rsi": 0.7, "trend": 0.3}, predicted=1.0, baseline=0.0,
))
led.record_outcome(OutcomeRecord(prediction_id="p1", actual=1.0))

scores = mature(led)   # [PredictionScore(accuracy=1.0, attributions={...})]

Weights / update / aggregate and predict_from_attributes / blend_strategies / best_strategy close the loop for the reweighting phase.

License

Apache-2.0. See LICENSE.